Optical switching device for directing the flow of light through waveguides in a electro-optic material are well known. Mach-Zehnder switches require long electrodes and carefully controlled drive voltages. Y-branch switches with small branch angles also require long electrodes. Both types of switches operate at frequencies of a few Giga-Hertz (GHz) or less, unless employing travelling-wave electrode structures.
Y-branch switches with larger branch angles e.g. 2.degree., required shorter electrodes. Applicant has described such a device in a paper titled "Y-Branch Optical Modulator" OE/FIBERS '91 Boston Mass. Sep. 3 to 6, 1991, Jaeger et al and "The Effects of Branch Angle on a Y-Branch Optical Modulator" given at The First Graduate Student Conference on Opto-Electronic Materials, Devices, and Systems Jun. 24-26 1991 McMaster University, Hamilton, Ontario, Canada by Lai both of which are incorporated herein by reference. However such a device requires a large drive voltage generally on the order of 50 volts. This large voltage rather than the channel length, limits the frequency due to difficulties in generating the required drive voltages. Because of the high voltage and the power losses associated with the operation of these devices, these devices have not found wide application.